Preparation of optically active alkoxy-serines from amino-amide racemate catalyzed by Escherichia coli cells with peptidase B activity

Alkoxy-L-serines are useful for peptide syntheses. The demand for alkoxy-L-serines in the pharmaceutical industries continues to increase because of their multiple physiological effects. In this research, an improved method for alkoxy-L-serines synthesis is reported. A series of substrates, DL-β-alkoxy-α-amino propionamides, was used for the synthesis of alkoxy-serines catalyzed by Escherichia coli cells with peptidase B(PepB) activity. The results show that PepB has a high resolution activity with DL-β-alkoxy-α-amino propionamides as substrate. Reaction conditions were optimized, i.e., DL-β-methoxy-α-amino propionamide as substrate at pH=9.0, 40 °C and 14 h, and the optimal reaction concentration is 400 mmol/L. The results also show that divalent metal cations exhibit different effects on the PepB activity, for example, Zn and Cu can obviously inhibit the activity of PepB, whereas Co, Ca, Mn and Mg at low concentrations can activate PepB. This research provides access to enantiomerically enriched and valuable alkoxy-L-serines from a simple amino-amide racemate. © 2012 Jilin University, The Editorial Department of Chemical Research in Chinese Universities and Springer-Verlag GmbH.